We use an empirical model of climate, trained by minimization of the model cost function to the observed global, monthly mean temperature anomaly from 1860 to present, to project how global mean temperature could rise over the next four decades. Our analysis extends to 2053, the year atmospheric CO2 is projected to reach 560 ppm (twice pre-industrial) according to the RCP 8.5 scenario developed for IPCC (2013). This presentation will focus on showing the sensitivity of projected future temperature to radiative forcing of climate due to tropospheric aerosols as well as ocean heat export. We will also compare our temperature projections to those inferred from GCM output maintained by the CMIP5 archive.